In Project 6 we will assess exposures to atmospheric PCBs among an urban cohort of children and their mothers in a heavily contaminated area where dredging and filling of PCB-laden sediments will occur during the study period. Exposures will be assessed through repeated air sampling over four years inside and outside of homes of subjects and at local schools and also through annual blood collection and assay for PCB congener profiles. These exposures will be compared to a rural site with the goal of characterizing atmospheric PCB exposures in high and low exposure residential cohorts. The urban site (East Chicago, IN) has a legacy of PCB contamination from intense past industrial activity whereas the rural site (Columbus Junction, IA) is without local sources of PCBs. The overall goal of the study is to establish airborne exposures of ethnically mixed populations, most and least at risk for adverse health outcomes from the more volatile PCBs. The following Specific Aims are proposed: Aim 1) Establish a residential cohort (n=108) in East Chicago. Aim 2) Establish a residential cohort (n=108) in Columbus Jet. Aim 3) Measure emissions and exposures of atmospheric PCBs at homes and schools over 4 years in the urban and rural cohorts. Aim 4) Gather demographic, residential, occupational, activity and dietary information from subjects by questionnaire. Aim 5) Analyze data from these cohorts and develop an exposure model for the atmospheric PCB congeners. The Indiana Harbor and Canal Dredging Project will place 4.5 million cubic yards of PCB-contaminated sediment into a confined disposal facility (CDF) located within 1/2 km of the middle and high school in East Chicago. Thus, we will perform air and blood monitoring of nearby residents before and during dredging and CDF filling and characterize determinants of exposure. Four primary hypotheses will be tested: H,: Residents of East Chicago have significantly higher exposures to atmospheric PCBs and (H2:) significantly higher blood levels of atmospheric PCB congeners than people living in rural Iowa. H3: In the urban cohort and the rural cohort, the body burden of the atmospheric PCB congeners of adolescent subjects are significantly correlated with those of their mothers. H4: Residents of East Chicago will experience significantly increased exposures to atmospheric PCBs and increased blood PCB concentrations associated temporally with the dredging of Indiana Harbor and placement of sediments in the confined disposal facility.